Composite sheet-metal work.



A. F. RIETZEL. l COMPOSITE SHEET METAL WORK.

APPLIOATION FILED 111311.14, 190s.

1,020,056. Patented Mar.12,1912.

r-W I /4 M UNTTED sTATEs PATENT OFFICE. ,l

ADOLPH F. RIETZEL, OF STONINGTON, CONNECTICUT, ASSIGNOR, BY MESNE'ASSIGN- MENTS, TO THOMSON ELECTRIC WELDING COMPANY, OF LYNN,MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS.

COMPOSITE SHEET-METAL WORK.

Specification of Letters Patent.

Application filed April 14, 1908. Serial No. 426.959.

of Stonington, in the State of Connecticut, have invented certain newand useful' Im.-

electricallyunited union as described in my prior application for patentfiled-Feb'. 24th, 1905, S. N. 247,081. ,ln structures of this character,it is frequently desirable that after the fastening ,of the platestogether has beeny effected by pressure applied to the plates while inan electric welding machine,

there shall be left a distinctspace between them, and the object of mypresent invention is to insure the 'production of thenished structurewith such space.

In the process of making the structure according to the manner describedin my prior application, the welded points ofv union are formed atprojected points or portions of the plates which, as therein described,are of such form that the application of the welding pressure willordinarily result in bringing the plane faces of the plates into directcontact with one another.

My present invention consists essentially in the provision, for eachwelded point of a base formed out of the metal of the .plate and of suchform or character that -it will not become softened by the applicationof the current but will remain cold and when the pressure is applied tothe plates in sufcient amount to make the weld, said base portionsurmounted by the finished weldedl portion will act as a stop that willkeep-fthe plates apart.

In the accompanying drawings, Flgure 1 is a cross section throughthe-two plates,

I, each provided with projections suitable for carrymg out my invention,the plates being here shown in the condition prior to the application ofthe heating current and pressure. Fig. 2 shows the iinished Work. Fig. 3shows in plan a portion of the work and illustrates the form of theprojection in .outline Fig. l ill` strates a modification.

Referring to Fig. 1, the tWo plates to be unitedare indicated at 1, l.The projec* tions formed upon the plates preliminary to the operation ofsecuring them together,

may be described as' consisting of-two portions, one of whichconstitutes the eXtremeportion 2 of the projection, and is theWeldingprojection, While the other portion 3 forms a base portion of theprojection surmounted by the portion 2 and does not become deformed oris so little deformed that it serves as a positive means for keeping theplates apart as shown in Fig. 2. As shown, the part 3 of theseprojections is much larger than the part 1narked'2, that is to say. thepart markedI 2 is the only part that'heats to welding temperature by thepassage of the electric current from one plate to the otherthrough suchparts 2, the heat notrunning back into the part 3 to .any great eX-tent, so that this portion of the metal is kept cold when the endpressure is applied to force the plates together hard enough to make agood weld, and theywill not come completely together, but will be leftin the Welded position shown in Fig. 2, in which the part termed thebase portion lies wholly below the plane of the welds. This is due tothefact that the base portion 3 is of such small dimensions that itWilleifectually resist the pressure tending to press it back into theplane of the plate When the Weldingend pressure is applied and will actpractically as a stop to limit the approach of the plates, leaving theWeld 'surm'ountingthe base so that the planev of the welds will bepractically coincident with a plane pass- .ing through the top of thebase portions 3.

The projecting portion 3 is very much larger than the portion 2 and theportion 2 rise from a plane face of the projection 3. In

.this instance the Contact and pressure electrode 4, instead of bearingupon the main surface of the plate may be made to apply the Weldingpressure Within the project-ing portion 3 thus localizing the pressureand.

obviating the tendency of the portion 3 to become forced 'back into t'heplane of the plate as would bathe. tendency 1f the elecratenta Mar.12,1912. l 1

trede bore against the s urface of the plate between projections as inthe arrangement illustrated in Fig. 1. Obviously, the electrodes may fitmore or less closely into the projections 3. The part 2 of the doubleprojection is the part which becomes involved in the welding, being thepart which is raised to welding temperature by the passage of theelectric current from one point to the other, as inthe process describedin my prior application before referred to, while the base projection 3becomes the spacing` projections should be on both o'f the plates.--They may be on one of them only as illustrated in Fig. 4t.

What l. claim as my invention is l. rl`he method of securing two platestogether with a space between them consisting in forming upon a plate adouble projection one portion of which is smaller than and surmounts theother or base portion and constitutes a welding projection, assembling'the plates face to face, passing a heating electric current from one tothe other through said welding projection and forcing theplates togetherto first weld them by the welding projections and then bring the baseportion into engagement thereby determining the space between 'theplates.

2. The method of securing two plates together with a space between them,consisting in forming-a multiplicity of double projections,'eachcomprising two parts, one of which forms a base portion and is very muchlarger than the other, while the latter projectsfarther from the planeof the plate than said larger portion, and securing the plates togetherby applying welding pressure within thebase portion until the projectionconstituting the base portion engages an opposite surface and at thesame time passing of heating electric current through the smallerportion of each projection, "as and for the purpose described.

The method of forming a composite sheet metal structure comprismg anumber of plates electrically united at a number of distinct points ofelectrically welded funon consisting in Vforming on the plateaprojecting portion having a plane face surmounted by another projectionof smaller size or area rising above said plane, arranging the platestogether faceto face, passing electric current from one to anotherthrough the smaller' projections and forcing the platesv together' untilthe saidplane face of the projection engages to determine the amount ofspace between the plates.

Signed at New York in the county of New York-and State of New York this3d day of April A. D. 1908.

. `ADoLPH r.l RIETZEL.

Witnesses C. F. FISCHER, JR., LILLIAN BLOND.

